The Mortal Instruments City of Fallen Angels

The worst instance of stalling for time was the fourth book, The Mortal Instruments City of Fallen Angels; it was so infuriating that I wrote a summary that meant to be funny, so others wouldn't have to suffer through it. I don't think you'd miss anything by skipping that book and jumping straight from book 3 to 5, using the summary which will make sense if you've read the previous three books. Unfortunately, the joke doesn't come across in English, sorry.